<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>移动端</title>
    <style>
        *{
            padding:0;
            margin:0;
        }
        #one{
            width: 200px;
            height: 200px;
            background-image: url("./img/logo.png");
        }
        #two{
            width: 200px;
            height: 200px;
            background-size: 100%;
            background-image: url("./img/logo@2x.png");
        }
        #three{
            width: 200px;
            height: 200px;
            background-size: 100%;
            background-image: url("./img/logo@3x.png");
        }
    </style>
</head>
<body>
    <div id="one"></div>
    <div id="two"></div>
    <div id="three"></div>
</body>
</html>